The operator expects to make a new service available to enterprise customers later this year

AT&T plans to test a service allowing payment card providers to access the location of a customer's phone to improve the accuracy of fraud prevention systems for transactions made abroad.

The service is part of AT&T's Location Information Services portfolio, and allows businesses to access network data to locate a device to authenticate a user's location, helping to protect against potential fraud. For the fraud protection to work, users will first have to opt in, AT&T said.

A credit card company can use the service to confirm someone has traveled to a new country as soon as they land and turn on their phone. The goal is to help credit card companies make more informed decisions, such as whether to approve or decline purchases made abroad.

The test will begin this summer, and AT&T expects to make the service available to enterprise customers later this year. The plan is to make it available in more than 150 countries, the operator said on Thursday.

Between 50 percent and 80 percent of declined transactions are actually legitimate, but they are turned down by financial institutions for security reasons, according to Mastercard.

Back in February, Mastercard and roaming infrastructure company Syniverse also announced the ability to protect credit card transactions abroad with the help of a phone's location.

Within less than 300 milliseconds a request goes from the payment terminal into Syniverse's platform, which keeps track of where roaming phones are located, and then information is returned about whether a transaction should be approved or denied, Syniverse said at the time.

AT&T's service is based on the operator's Mobile Identity API Toolkit, which launched in December last year.